1. Field of the Invention
The present invention relates to a burner for operating a combustion chamber.
2. Discussion of Background
EP-0 704 657 has already disclosed a burner which consists of a swirl generator on the incident-flow side, the flow formed herein being passed smoothly into a mixing section. This is done with the aid of a transition geometry, which is formed at the start of the mixing section for this purpose and consists of transition passages which cover sectors of the end face of the mixing section, in accordance with the number of acting sectional bodies of the swirl generator, and run helically in the direction of flow. On the outflow side of these transition passages, the mixing section has a number of prefilming bores, which ensure that the flow velocity along the tube wall is increased. This is then followed by a combustion chamber, the transition between the mixing section and the combustion chamber being formed by a jump in cross section, in the plane of which a backflow zone or backflow bubble forms.
The swirl intensity in the swirl generator is therefore selected in such a way that the breakdown of the vortex does not take place inside the mixing section but further downstream, as explained above in the region of the jump in cross section. The length of the mixing section is dimensioned in such a way that an adequate mixing quality is ensured for all types of fuel.
Although this burner, compared with those from the prior art, has brought about a significant improvement with regard to intensification of the flame stability, lower pollutant emissions, lower pulsations, complete burn-out, large operating range, good cross ignition between the various burners, compact type of construction, improved mixing, etc., it is found that a further intensification of the flame stability as well as an improved adaptation of the flame to the predetermined geometry of the combustion chamber has become necessary for smooth operation at the highest level in the premix combustion of the newer generation.